A paddle is a tool used for pushing against liquids, either as a form of propulsion of a boat (paddling) or as an implement for mixing. Canoe and kayak paddles = Materials and designs =Paddles commonly used in canoes consist of a wooden, fibreglass, carbon fibre, or metal rod (the shaft) with a handle on one end and a rigid sheet (the blade) on the other end. Paddles for use in kayaks are longer, with a blade on each end, they are handled from the middle of the shaft. Kayak paddles having blades in the same plane (when viewed down the shaft) are called 'un-feathered. ' Paddles with blades in different planes are called 'feathered'. Feathered paddles are measured by the degree of feather, such as 30, 45, or even 90 degrees. Many modern paddles are made of two pieces which can be snapped together in either feathered or unfeathered settings. The shaft is normally straight but in some cases a 'crank' is added with the aim of making the paddle more comfortable and reducing strain on the wrist. Because the kayak paddle is not supported by the boat, paddles made of lighter materials are desired, it is not uncommon for a kayak paddle to be two pounds (32 ounces (910 grams) ) or less and very expensive paddles can be as light as 22 ounces (620 grams). Weight savings are more desirable at the ends of the paddle rather than in the middle. Cheaper kayak paddles have an aluminium shaft while more expensive ones use a lighter fibreglass or carbon fibre shaft.